| Conversion of carbon dioxide to desirable, economically competitive products has received much attention because of its potential use as an abundant carbon resource and its indirect role as an environmental pollutant. The Salen complex is an efficient catalyst for CO2 with epoxide reaction which developed in recent years. However, it is difficult to be separated in the homogeneous reaction, and it is also easy to form the oxygen bridged two dimers of -oxo-Mn (Ⅵ), which makes it difficult to achieve industrial production. Nowadays, what we need do is to immobilize the Salen complexes in carriers. Poly aniline and its derivatives have special electronic effects, physical stability. So in this paper the modified polyaniline derivatives were used as a carrier and salen complexes was supported on the carrier with the coordination bond. The copolymerization of carbon dioxide with epoxy cyclohexane which catalysted by supported catalyst was also studied.1. In the experimental process, the analysis of MPOAP, MPOAP-SalenCrⅢCl and SalenCrmCl were made by the means of UV, IR, XRD, SEM, TEM, XPS, ICP and so on. The results indicated that SalenCrⅢCl was successfully supported on the MPOAP.2. The supported catalyst was applied to the copolymerization of carbon dioxide with epoxy cyclohexane, and the The effects of the copolymerization activity, molecular weight, molecular weight distribution, thermal stability, glass transition temperature of the products were analyzed using different amount of SalenCrⅢCl, monomeric amino phenol, and doping different acids with different methods in MPOAP. In the experimental process, TG、DTG and GPC were made to the analysis of reaction. The analysis results indicated that when a small amount of SalenCrⅢCl was used to the copolymerization of CO2 and CHO, the active centers of cocatalyst will compete with the monomer which will impede the growth of polymer chains and the activity of the catalyst was reduced. With increasing the amount of homogeneous SalenCrⅢCl the molecular weight of the product and activity of polymerization began to increase. However, when we continue increase the amount SalenCrⅢCl, it will hinder the growth of molecular chain and reduce molecular weight of products, even though monomer can be consumed completely. The results also indicated that the modified polyaniline derivatives were used as a carrier and salen complexes was supported on the carrier with the coordination bond. Based on the thermodynamic analysis, it showed that the optimal dosage of ortho amino phenol monomer in carrier is 0.3M. The best catalyst is synthesized with interfacial polymerization and doped with sulfuric acid.3. Compared with homogeneous catalyst SalenCrⅢCl, the influence of immobilized catalyst MPOAP-SalenCrⅢCl in the selectivity of chain segments and regional regularity was analyzed preliminaryly. We could not find the existence of byproducts cyclic carbonate in the copolymerization catalyzed by supported catalyst MPOAP-SalenCrⅢCl. Additionaly, the chain structure of the products catalyzed by supported catalyst was more likely to form ester segment, and the content of ether chain segment was lower than the product catalyzed by homogeneous catalyst SalenCrⅢCl under same conditions. Morover, the ratio of isotactic and syndiotactic was 1:0.95 in product catalyzed by supported catalyst MPOAP-SalenCrⅢCl. Howerver, the corresponding value of isotactic and syndiotactic in product catalyzed by homogeneous catalyst SalenCrⅢCl was 1:0.80. This indicated that the immobilization had a significant effect on the regioregularity in product.4. With doping chiral camphor sulfonic acid in the carrier of supported catalyst MPOAP-SalenCrⅢCl, we have analyzed the influence of chiral acid in the carrier of supported catalyst. For comparison, supported catalyst MPOAP-SalenCrⅢCl which doped with H2SO4 was also used to canalyze the selectivity of the reaction products, segments and segments regioregularity. The results showed that the catalyst doped with chiral camphor sulfonic acid was similar to the catalyst doped with sulfuric acid. Both of them without cyclic carbonate generating. Importantly, with the introduction of chiral acid, the carbonate bond unit content was 94.7% in the copolymerization catalyzed by supported catalyst MPOAP-SalenCrⅢCl, which doped with chiral camphor sulfonic acid. The corresponding value of catalyst doped with H2SO4 was 96.0%. Howerver, the regioregularity of product catalyzed by the supported catalyst doped with chiral camphor sulfonic acid was much higher than supported catalyst... |
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